Life term concerns

A few years ago, I changed my view on the death penalty and now believe that the state has no right to kill, whether it be a despicable, incorrigible murderer or a totally innocent unborn baby. I'm glad New Jersey has abandoned the death penalty.
But I'm troubled by the alternative. Life in prison without parole raises questions. First, what's to prevent a legislature from changing the law to allow parole? What's to prevent a governor from commuting a life sentence or pardoning a murdering lifer? We need assurance this will never happen.
Second, these criminals must spend their lives in some discomfort. By definition, there is no rehabilitation for these convicts, so let's incarcerate them in an environment that's cold in winter and hot in summer, where the food is nutritious but tasteless and where entertainment of any sort is excluded.
Third, since these people can suffer no greater penalty, they must be confined in a prison where they are no danger to guards or administrators. Perhaps a dedicated prison for lifers would be the solution. If these concerns were addressed, many death penalty supporters would change their view.